Shortly after the squad's deployment, the group is attacked by an abnormalTitan, which results in the death of Thomas Wagner. This causes Eren to attack the aberrant in a rage. Mylius warns Eren not to go alone, which in turn causes his squad to pursue and try to help him. Following the death of fellow trainee Nac Tias, the squad is attacked by a group of Titans, and Mylius is caught by yet another Titan. Armin can only watch in shock and horror as both Mylius and Mina Carolina, struggling, screaming, and begging for their lives, are eaten.[2] Armin later reports Mylius' demise to the remaining members of the 104th Training Corps, saying he died valiantly in the line of duty.[3]

His death is later avenged by Eren in his Titan form, who kills the Titan responsible for Mylius' demise by brutally punching it in its mouth and repeatedly stomping it into the ground.[4]